In a children’s flu study, researchers said Danish scientists recently discovered that vitamin D triggers immune-system killer T-cells—white blood cells that attack viruses—but remain inactive when vitamin D is low. In this study, 334 kids took 1,200 IU of vitamin D per day or a placebo from December through March. Over this time, 19 percent in the placebo group got influenza A compared to 11 percent for vitamin D. In those with asthma, 12 in the placebo group had an asthma attack compared to two in the vitamin D group. The researchers believe vitamin D could have been even more effective in preventing flu because it takes about three months to build up a base level in the blood, and the study began after flu season had started.

In a related study, researchers measured vitamin D levels in 195 men and women, aged 20 to 88, during the fall and winter. Over four months, 84 participants got viral infections. In those whose vitamin D levels were lower than 38 nanograms per milliliter of blood, 55 percent had no respiratory tract infection. In those whose vitamin D levels were higher, 83 percent had no infection.

In two lab studies, researchers exposed white-blood killer T-cells to influenza A and other viruses before and after healthy donors had taken the probiotic Bacillus coagulans or 15 mg of zinc per day for the previous month. In both studies, killer T-cell activity significantly increased after taking probiotics or zinc.

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.

Information provided on this site is solely for informational purposes only.
It is not a substitute for professional medical advice. Do not use this information for
diagnosing or treating a health problem or disease, or prescribing of any medications or
supplements. Only your healthcare provider should diagnose your healthcare problems and
prescribe treatment. None of our statements or information, including health claims, articles,
advertising or product information have been evaluated or approved by the United States Food
and Drug Administration (FDA). The products or ingredients referred to on this site are
not intended to diagnose, treat, cure or prevent any disease. Please consult your healthcare
provider before starting any supplement, diet or exercise program, before taking any medications
or receiving treatment, particularly if you are currently under medical care. Make sure you
carefully read all product labeling and packaging prior to use. If you have or suspect you
may have a health problem, do not take any supplements without first consulting and obtaining
the approval of your healthcare provider.
California Consumers – Proposition 65 requires sellers to notify California consumers
of substances that are in many foods, plants, herbs and supplements with the following warning.
WARNING: These products contain chemicals known to the State of California to cause birth
defects or other reproductive harm.